The findings may help explain why women are two to four times more likely to have CFS than men, and why the condition is most common among women in their 40s, the researchers from the U.S. Centers for Disease Control and Prevention said.

"CFS can take a tremendous toll on women's lives at midlife and on our society and health care system. Being aware of the association of CFS and earlier menopause can help providers assist women in sorting out symptoms of CFS from symptoms of menopause," Dr. Margery Gass, executive director of the North American Menopause Society, said in a society news release.

Although the study was able to find a link between early menopause and chronic fatigue syndrome, the researchers weren't able to learn whether one condition causes the other, or if there's another factor that might cause both conditions.

Results of the study were published online Feb. 4 in the journal Menopause.

The study included 84 women and a control group of 73 healthy women in Georgia who provided information about their gynecological health.

Compared to those in the control group, the women with chronic fatigue syndrome were 12 times more likely to have pelvic pain that wasn't related to menstruation. They were also more likely to have excessive menstrual bleeding (74 percent vs. 42 percent) and more bleeding between periods (49 percent vs. 23 percent). The researchers also found that women with CFS were also more likely to miss periods (38 percent vs. 22 percent).

Women with chronic fatigue syndrome were more likely (57 percent vs. 26 percent) to use hormones for purposes other than birth control, such as to treat irregular periods, menopausal symptoms or bone loss, than women without the condition.

The study also found that 66 percent of women with CFS had undergone at least one gynecologic surgery, compared with 32 percent of those in the control group. The most common type of surgery was hysterectomy (55 percent vs. 19 percent).

Hysterectomy-related early menopause (at or before age 45) occurred in 62 percent of women with chronic fatigue syndrome, compared with 33 percent of those in the control group. Bleeding as the reason for hysterectomy was much more common among women with CFS.

Women with CFS also tended to undergo natural menopause earlier than those in the control group, but there was not a significant difference between the two groups, according to the study.

Previous research has linked chronic fatigue syndrome with pelvic pain and gynecologic conditions, such as endometriosis and menstrual abnormalities. But this is the first study to link CFS with early menopause, according to the study authors.

They said further research is needed to learn more about this possible link, and that doctors need to watch for symptoms of CFS in women who have gynecologic or pelvic pain problems. Symptoms of CFS include muscle and joint pain, sleep or memory difficulties, and a worsening of these problems after exertion.